The present invention relates generally to telecommunications, and more particularly to the lawful intercept of telephony communications in a telecommunications network using Signaling System 7 (SS7).
Court authorized access to telephone communications and call-identifying information is one of the most crucial tools for effective law enforcement. The introduction of new digitally based technologies, transmission modes, services, and features have made it increasingly difficult for law enforcement to conduct court authorized electronic surveillance. In October of 1994, at the request of the nation""s law enforcement community, Congress took action to protect public safety and national security by enacting the Communications Assistance for Law Enforcement Act (CALEA). CALEA sets forth the interception assistance capability requirements that telecommunications carriers need to meet and maintain within their networks to assist law enforcement in conducting electronic surveillance. These requirements apply to the intercept of wireline and wireless communications.
In order to meet the requirements of law enforcement to intercept communications, the telecommunications industry has defined an interface specification between a Telecommunication Service Provider (TSP) and a Law Enforcement Agency (LEA), called the J-STD-025 (Lawfully Authorized Electronic Surveillance). The J-STD-025, xe2x80x9cLawfully Authorized Electronic Surveillancexe2x80x9d, is a joint standard by the Telecommunications Industry Association (TIA) Committee TR45.2 and the Alliance for Telecommunications Industry Solutions (ATIS) Committee T1-Telecommunications. Compliance to J-STD-025 is seen by the telecommunications industry as xe2x80x9csafe harborxe2x80x9d under Section 107 of the CALEA, Public Law 103-414.
J-STD-025 views the intercept function as five broad categories: access, delivery, collection, service provider administration, and law enforcement administration. The relationships between these functional categories are shown in FIG. 1. As illustrated in FIG. 1, the Service Provider Administration Function 10 is responsible for controlling the TSP access and delivery functions. The Law Enforcement Administration Function 11 is responsible for controlling the LEA collection functions. The access function 14, consisting of one or more Intercept Access Points (IAPs), isolates an intercept subject""s communications or callidentifying information unobtrusively. The access function 14 provides access to communications traversing a telecommunications network. The delivery function 16 is responsible for accepting information from one or more access functions 14 and delivering intercepted communications to one or more collection functions 18. The delivery function 16 delivers information over two distinct types of channels: Call Content Channels (CCCs) and Call Data Channels (CDCs). The CCCs are generally used to transport call content, such as voice or data communications. The CDCs are generally used to transport messages which report call-identifying information, such as calling party identities and called party identities. The collection function 18 is responsible for collecting and analyzing intercepted communications and call-identifying information. The collection function 18 is the responsibility of the LEA.
The present invention provides method and apparatus for intercepting calls for a subject under surveillance (SUS) in a Signaling System 7 (SS7) compliant telephone system, or a telephone system with equivalent relevant functions, by forwarding calls for a SUS from the end office switch to a delivery function, which in turn forwards the calls back to the end office switch for further processing, and in addition obtains call content and information as the call passes through the delivery function. The delivery function can in turn deliver call content and information to a collection function.